U.S. patent application number 14/244152 was filed with the patent office on 2015-04-23 for method and apparatus for optimizing coverage area of a small cell.
This patent application is currently assigned to QUALCOMM Incorporated. The applicant listed for this patent is QUALCOMM Incorporated. Invention is credited to Vinay CHANDE, Tao CHEN, Farhad MESHKATI, Rajat PRAKASH, Mehmet YAVUZ.
Application Number | 20150111589 14/244152 |
Document ID | / |
Family ID | 52826607 |
Filed Date | 2015-04-23 |
United States Patent
Application |
20150111589 |
Kind Code |
A1 |
YAVUZ; Mehmet ; et
al. |
April 23, 2015 |
METHOD AND APPARATUS FOR OPTIMIZING COVERAGE AREA OF A SMALL
CELL
Abstract
The present disclosure presents a method and an apparatus for
optimizing coverage area of a small cell. For example, the
disclosure presents a method for estimating an available backhaul
capacity of a small cell and determining a target OTA data rate for
the small cell based at least on the estimated available backhaul
capacity, and changing a coverage area of the small cell based at
least on the determined target OTA data rate by. As such,
optimizing coverage area of a small cell may be achieved.
Inventors: |
YAVUZ; Mehmet; (San Diego,
CA) ; MESHKATI; Farhad; (San Diego, CA) ;
PRAKASH; Rajat; (San Diego, CA) ; CHEN; Tao;
(San Diego, CA) ; CHANDE; Vinay; (San Diego,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
QUALCOMM Incorporated |
San Diego |
CA |
US |
|
|
Assignee: |
QUALCOMM Incorporated
San Diego
CA
|
Family ID: |
52826607 |
Appl. No.: |
14/244152 |
Filed: |
April 3, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61892987 |
Oct 18, 2013 |
|
|
|
Current U.S.
Class: |
455/452.1 ;
455/561 |
Current CPC
Class: |
H04W 52/244 20130101;
H04W 24/02 20130101; H04W 52/343 20130101; H04W 16/32 20130101;
H04W 52/267 20130101; H04W 72/0486 20130101; H04W 16/08
20130101 |
Class at
Publication: |
455/452.1 ;
455/561 |
International
Class: |
H04W 72/04 20060101
H04W072/04; H04W 24/02 20060101 H04W024/02; H04W 52/26 20060101
H04W052/26 |
Claims
1. A method for optimizing a coverage area of a small cell,
comprising: estimating an available backhaul capacity of a small
cell; determining a target over the air (OTA) data rate for the
small cell based at least on the estimated available backhaul
capacity; and changing the coverage area of the small cell based at
least on the determined target OTA data rate.
2. The method of claim 1, wherein the coverage area of the small
cell is changed by modifying one or more parameters of the small
cell.
3. The method of claim 2, wherein the target OTA data rate is
achieved by reducing available resource elements (RE) at the small
cell.
4. The method of claim 2, wherein the changing of the coverage area
of the small cell further comprises increasing transmit power per
resource element (RE) at the small cell.
5. The method of claim 2, further comprising: increasing transmit
power of one or more common channels of the small cell.
6. The method of claim 5, wherein the one or more common channels
are selected from a list comprising a common reference signal
(CRS), a primary synchronization signal (PSS), a secondary
synchronization signal (SSS), a physical broadcast channel (PBCH),
and a physical downlink control channel (PDCCH).
7. The method of claim 2, wherein the coverage area of the small
cell is changed by modifying an operating bandwidth or a
traffic-to-pilot ratio of the small cell.
8. An apparatus for optimizing a coverage area of a small cell,
comprising: means for estimating an available backhaul capacity of
a small cell; means for determining a target over the air (OTA)
data rate for the small cell based at least on the estimated
available backhaul capacity; and means for changing the coverage
area of the small cell based at least on the determined target OTA
data rate.
9. The apparatus of claim 8, wherein the coverage area of the small
cell is changed by modifying one or more parameters of the small
cell.
10. The apparatus of claim 9, wherein the target OTA data rate is
achieved by reducing available resource elements (RE) at the small
cell.
11. The apparatus of claim 9, wherein the changing of the coverage
area of the small cell further comprises increasing transmit power
per resource element (RE) at the small cell.
12. The apparatus of claim 9, further comprising: means for
increasing transmit power of one or more common channels of the
small cell.
13. The apparatus of claim 12, wherein the one or more common
channels are selected from a list comprising a common reference
signal (CRS), a primary synchronization signal (PSS), a secondary
synchronization signal (SSS), a physical broadcast channel (PBCH),
and a physical downlink control channel (PDCCH).
14. The apparatus of claim 9, wherein the coverage area of the
small cell is changed by modifying an operating bandwidth or a
traffic-to-pilot ratio of the small cell.
15. A computer program product for optimizing a coverage area of a
small cell, comprising a non-transitory computer-readable medium
comprising code executable by a computer for: estimating an
available backhaul capacity of a small cell; determining a target
over the air (OTA) data rate for the small cell based at least on
the estimated available backhaul capacity; and changing the
coverage area of the small cell based at least on the determined
target OTA data rate.
16. The computer program product of claim 15, wherein the coverage
area of the small cell is changed by modifying one or more
parameters of the small cell.
17. The computer program product of claim 16, wherein the target
OTA data rate is achieved by reducing available resource elements
(RE) at the small cell.
18. The computer program product of claim 16, wherein the changing
of the coverage area of the small cell further comprises increasing
transmit power per resource element (RE) at the small cell.
19. The computer program product of claim 16, further comprising:
code for increasing transmit power of one or more common channels
of the small cell.
20. The computer program product of claim 19, wherein the one or
more common channels are selected from a list comprising a common
reference signal (CRS), a primary synchronization signal (PSS), a
secondary synchronization signal (SSS), a physical broadcast
channel (PBCH), and a physical downlink control channel
(PDCCH).
21. The computer program product of claim 16, wherein the coverage
area of the small cell is changed by modifying an operating
bandwidth or a traffic-to-pilot ratio of the small cell.
22. An apparatus for optimizing a coverage area of a small cell,
comprising: a backhaul capacity estimating component to estimate an
available backhaul capacity of a small cell; a target over the air
(OTA) data rate determining component to determine a target OTA
data rate for the small cell based at least on the estimated
available backhaul capacity; and a parameter optimization component
to change the coverage area of the small cell based at least on the
determined target OTA data rate.
23. The apparatus of claim 22, wherein the parameter optimization
component is further configured to change the coverage area of the
small cell by modifying one or more parameters of the small
cell.
24. The apparatus of claim 23, wherein the target OTA data rate
determining component target is further configured to achieve the
OTA data rate by reducing available resource elements (RE) at the
small cell.
25. The apparatus of claim 23, wherein the parameter optimization
component is further configured to change the coverage area of the
small cell by increasing transmit power per resource element (RE)
at the small cell.
26. The apparatus of claim 23, wherein the parameter optimization
component is further configured to increase transmit power of one
or more common channels of the small cell.
27. The apparatus of claim 26, wherein the one or more common
channels are selected from a list comprising a common reference
signal (CRS), a primary synchronization signal (PSS), a secondary
synchronization signal (SSS), a physical broadcast channel (PBCH),
and a physical downlink control channel (PDCCH).
28. The apparatus of claim 22, wherein the coverage of the small
cell is changed by modifying an operating bandwidth or a
traffic-to-pilot ratio of the small cell.
Description
CLAIM OF PRIORITY UNDER 35 U.S.C. .sctn.119
[0001] The present application for patent claims priority to U.S.
Provisional Patent Application No. 61/892,987, filed Oct. 18, 2013,
entitled "Apparatus and Method for Optimizing Coverage Area of a
Small Cell," which is assigned to the assignee hereof, and hereby
expressly incorporated by reference herein.
BACKGROUND
[0002] The present disclosure relates generally to communication
systems, and more particularly, to a method and an apparatus for
optimizing coverage area of a small cell.
[0003] Wireless communication systems are widely deployed to
provide various telecommunication services such as telephony,
video, data, messaging, and broadcasts. Typical wireless
communication systems may employ multiple-access technologies
capable of supporting communication with multiple users by sharing
available system resources (e.g., bandwidth, transmit power).
Examples of such multiple-access technologies include code division
multiple access (CDMA) systems, time division multiple access
(TDMA) systems, frequency division multiple access (FDMA) systems,
orthogonal frequency division multiple access (OFDMA) systems,
single-carrier frequency division multiple access (SC-FDMA)
systems, and time division synchronous code division multiple
access (TD-SCDMA) systems.
[0004] These multiple access technologies have been adopted in
various telecommunication standards to provide a common protocol
that enables different wireless devices to communicate on a
municipal, national, regional, and even global level. An example of
an emerging telecommunication standard is Long Term Evolution
(LTE). LTE is a set of enhancements to the Universal Mobile
Telecommunications System (UMTS) mobile standard promulgated by
Third Generation Partnership Project (3GPP). It is designed to
better support mobile broadband Internet access by improving
spectral efficiency, lower costs, improve services, make use of new
spectrum, and better integrate with other open standards using
OFDMA on the downlink (DL), SC-FDMA on the uplink (UL), and
multiple-input multiple-output (MIMO) antenna technology. However,
as the demand for mobile broadband access continues to increase,
there exists a need for further improvements in LTE technology.
Preferably, these improvements should be applicable to other
multi-access technologies and the telecommunication standards that
employ these technologies.
[0005] To supplement conventional base stations, additional
restricted power or restricted coverage base stations, referred to
as small coverage base stations or cells, can be deployed to
provide more robust wireless coverage to mobile devices. For
example, wireless relay stations and low power base stations (e.g.,
which can be commonly referred to as Home NodeBs or Home eNBs,
collectively referred to as H(e)NBs, femto nodes, pico nodes, etc.)
can be deployed for incremental capacity growth, richer user
experience, in-building or other specific geographic coverage,
and/or the like. Such low power or small coverage (e.g., relative
to macro network base stations or cells) base stations can be
connected to the Internet via broadband connection (e.g., digital
subscriber line (DSL) router, cable or other modem, etc.), which
can provide the backhaul link to the mobile operator's network.
Thus, for example, the small coverage base stations can be deployed
in user homes to provide mobile network access to one or more
devices via the broadband connection. Because deployment of such
base stations is unplanned, low power base stations can interfere
with one another where multiple stations are deployed within a
close vicinity of one another.
[0006] In some small cell deployments, for example, neighborhood
small cells, there may be limitations on the backhaul in terms of
maximum supported throughout. However, in such deployments, the
over the air (OTA) data rates supported by the small may exceed the
backhaul capacity of the small cell resulting in inefficient use of
the OTA resources.
[0007] Thus, there is a desire for a method and an apparatus for
optimizing coverage area of a small cell.
SUMMARY
[0008] Various aspects are now described with reference to the
drawings. In the following description, for purposes of
explanation, numerous specific details are set forth in order to
provide a thorough understanding of one or more aspects. It may be
evident, however, that such aspect(s) may be practiced without
these specific details. The following presents a simplified summary
of one or more aspects in order to provide a basis understanding of
such aspects.
[0009] The present disclosure presents an example method and
apparatus for optimizing coverage area of a small cell. For
example, the present disclosure presents an example method for
estimating an available backhaul capacity of a small cell,
determining a target OTA data rate for the small cell based at
least on the estimated available backhaul capacity, and changing a
coverage area of the small cell based at least on the determined
target OTA data rate.
[0010] In an additional aspect, an apparatus for optimizing
coverage area of a small cell is disclosed. The apparatus may
include means for estimating an available backhaul capacity of a
small cell, means for determining a target OTA data rate for the
small cell based at least on the estimated available backhaul
capacity, and means for changing a coverage area of the small cell
based at least on the determined target OTA data rate.
[0011] In a further aspect, a computer program product for
optimizing coverage area of a small cell is described. The computer
program product may include a computer-readable medium comprising
code executable by a computer for estimating an available backhaul
capacity of a small cell, determining a target OTA data rate for
the small cell based at least on the estimated available backhaul
capacity, and changing a coverage area of the small cell based at
least on the determined target OTA data rate.
[0012] Moreover, the present disclosure presents an apparatus for
optimizing coverage area of a small cell. The apparatus may include
a backhaul capacity estimating component to estimate an available
backhaul capacity of a small cell, a target OTA data rate
determining component to determine a target OTA data rate for the
small cell based at least on the estimated available backhaul
capacity, and a parameter optimization component to change a
coverage area of the small cell based at least on the determined
target OTA data rate.
[0013] To the accomplishment of the foregoing and related ends, the
one or more aspects comprise the features hereinafter fully
described and particularly pointed out in the claims. The following
description and the annexed drawings set forth in detail certain
illustrative features of the one or more aspects. These features
are indicative, however, of but a few of the various ways in which
the principles of various aspects may be employed, and this
description is intended to include all such aspects and their
equivalents.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 is a block diagram illustrating an example wireless
system in aspects of the present disclosure;
[0015] FIG. 2 is a block diagram illustrating an example coverage
optimization manager in aspects of the present disclosure;
[0016] FIG. 3 is a flow diagram illustrating aspects of a method of
distributed optimization of a self organizing network;
[0017] FIG. 4 is a block diagram illustrating aspects of a logical
grouping of electrical components as contemplated by the present
disclosure;
[0018] FIG. 5 is a illustrates an exemplary communication system to
enable deployment of small cells within a network environment;
[0019] FIG. 6 is a block diagram illustrating aspects of a computer
device according to the present disclosure;
[0020] FIG. 7 is a block diagram illustrating an example of a
hardware implementation for an apparatus employing a processing
system;
[0021] FIG. 8 is a block diagram conceptually illustrating an
example of a telecommunications system;
[0022] FIG. 9 is a conceptual diagram illustrating an example of an
access network; and
[0023] FIG. 10 is a block diagram conceptually illustrating an
example of a NodeB in communication with a UE in a
telecommunications system.
DETAILED DESCRIPTION
[0024] The detailed description set forth below in connection with
the appended drawings is intended as a description of various
configurations and is not intended to represent the only
configurations in which the concepts described herein may be
practiced. The detailed description includes specific details for
the purpose of providing a thorough understanding of various
concepts. However, it will be apparent to those skilled in the art
that these concepts may be practiced without these specific
details. In some instances, well known structures and components
are shown in block diagram form in order to avoid obscuring such
concepts.
[0025] The present disclosure presents an example method and
apparatus for optimizing coverage area of a small cell. For
example, the data rates supported by a small cell may be limited by
the available backhaul capacity of the small cell. Therefore, a
target over the air (OTA) data rate is determined that is based at
least on the available backhaul capacity and the coverage area of
the small cell is changed (e.g., increased) to cover more area
and/or UEs that otherwise would not be covered by the small
cell.
[0026] Referring to FIG. 1, a wireless communication system 100 is
illustrated that facilitates optimizing coverage area of a small
cell.
[0027] In an aspect, for example, system 100 may be a
communications network that may include one or more base stations,
for example, a small cell 110 in communication with a core network
entity 102 via one or more communication links, for example, a link
104. System 100 may include one or more user terminals, for
example, UE 122 in a coverage area 120 of small cell 110. The UE
122 may be in communication with the small cell over one or more
over the air (OTA) links 116. FIG. 1 shows multiple UEs 122 in the
coverage area 120 of small cell 110.
[0028] The term "small cell," as used herein, refers to a
relatively low transmit power and/or a relatively small coverage
area cell as compared to a transmit power and/or a coverage area of
a macro cell. Further, the term "small cell" may include, but is
not limited to, cells such as a femto cell, a pico cell, access
point base stations, Home NodeBs, femto access points, or femto
cells. For instance, a macro cell may cover a relatively large
geographic area, such as, but not limited to, several kilometers in
radius. In contrast, a pico cell may cover a relatively small
geographic area, such as, but not limited to, a building. Further,
a femto cell also may cover a relatively small geographic area,
such as, but not limited to, a home, or a floor of a building.
[0029] In an aspect, small cell 110 may be configured with a
coverage optimization manager 112. The coverage optimization
manager 112 facilitates optimizing coverage area of small cell 110.
The coverage optimization manager 112 may optimize coverage area of
the small cell by estimating an available backhaul capacity of a
small cell, determining a target OTA data rate for the small cell
based at least on the available backhaul capacity, and changing the
coverage area of the small cell based at least on the determined
target OTA data rate.
[0030] In an additional aspect, coverage optimization manager 112
may be configured to include a parameter optimization component
114. The parameter optimization component 112 changes, for example,
increases or decreases, the coverage area of the small cell, by
modifying one or more parameters of the small cell. For example, in
an aspect, coverage optimization manager 112 may increase the
coverage area of the small cell from coverage area 120 to coverage
area 130 by modifying one or more parameters of the small cell. In
an aspect, the parameters modified for increasing (or decreasing)
the coverage area of the small cell may include transmit power of
the small cell, number of resource elements at the small cell,
transmit power of the pilot channels, operating bandwidth of the
small cell, traffic-to-pilot ratio, etc. which are described below
in detail.
[0031] In an additional or optional aspect, for example, coverage
optimization manager 112 may decrease the coverage area of the
small cell from coverage area 120 to coverage area 140 by modifying
one or more parameters of the small cell. For example, in an
aspect, the coverage area of small cell 110 may be decreased when
it determined that the available backhaul capacity can support
higher over the air (OTA) data rates at the UE.
[0032] Referring to FIG. 2, an example coverage optimization
manager in aspects of the present disclosure is illustrated.
[0033] In an aspect, coverage optimization manager 112, for
example, of small cell 110, may be configured to include a backhaul
capacity estimating component 210, a target OTA data rate
determining component 212, and/or parameter optimization component
114.
[0034] In an aspect, backhaul capacity estimating component 210 may
be configured to estimate available backhaul capacity of the small
cell. For example, in an aspect, backhaul capacity estimating
component 210 of small cell 110 may be configured to estimate the
available capacity of link 104 which is used by small cell 110 to
communicate with core network entity 102 for supporting one or more
of UEs 122.
[0035] The backhaul capacity of small cell 110 that is available
for UE 122 may depend on various factors. For example, in an
aspect, link 104 may be shared with other wired/wireless devices on
the small cell, e.g., Wi-Fi router, set top boxes, Wi-Fi TV, etc.
thereby reducing the backhaul capacity available for UE 122. In an
additional aspect, link 104 may encounter congestion that may
affect the available backhaul capacity for supporting UE 122. In a
further additional aspect, the available backhaul capacity for UE
122 may be dependent on the type of backhaul, e.g., fiber, digital
subscriber line (DSL), cable modem, Ethernet, etc.
[0036] In an aspect, the available capacity of the backhaul may be
estimated using several techniques. For example, in an aspect, the
available capacity of the backhaul (e.g., link 104) may be
estimated using light probing or heavy probing. In an additional
aspect, the available capacity of the backhaul may be estimated by
initiating a small download session over link 104 from a known
server. In a further additional aspect, for example, the available
capacity of backhaul 104 may be estimated by measuring round trip
time (RTT) delays.
[0037] In an aspect, target OTA data rate determining component 212
may be configured to determine a target OTA data rate for the small
cell based at least on the available backhaul capacity. For
example, in an aspect, target OTA data rate determining component
212 may determine the target OTA data rate for small cell 110 based
on the estimated available capacity of link 104.
[0038] For example, in an aspect, when estimated available backhaul
capacity is 10 Mbps, target OTA data rate determining component 212
may determine that the target OTA rate for the small cell to be a
value at or below 10 Mbps as the small cell may not be able to
support data rates over 10 Mbps due to backhaul limitations. If the
target OTA data rate is configured to a value above 10 Mbps, the
OTA resources of the small cell are not being used efficiently. In
an additional or optional aspect, a peak OTA data rate may be
identified based on the configuration of the small cell. For
example, in an aspect, peak OTA data rate supported by the small
cell may be determined based on number of antennas and/or antenna
configuration at the small cell.
[0039] In an aspect, parameter optimization component 114 may be
configured to change coverage area of the small cell based on the
determined target OTA data rate by modifying one or more parameters
of the small cell. For example, in an aspect, the coverage area of
small cell 110 may be changed based on the determined target OTA
data rate by modifying one or more parameters of the small
cell.
[0040] For example, the transmit power per resource element (RE) of
the small cell may be increased to increase the coverage area of
the small cell. The increased transmit power per RE of the small
cell may provide extended coverage to enable the small cell to
provide service to UEs that otherwise would have been outside the
coverage of the small cell. For example, coverage area 130 in FIG.
1 illustrates an aspect where the coverage area of the small cell
is increased, for example, by increasing the transmit power per RE
of the small cell, which in turn may be able to provide service to
one or more of UEs 132.
[0041] In an aspect, the number of resource elements at the small
cell may be reduced when the transmit power per RE of the small
cell is increased as the small cell may not use all the REs anyway
due to limitations with the backhaul. In an additional aspect, this
may allow for increasing the coverage area of the small cell by
increasing the transmit power of the small cell. For example, the
cell coverage area may be increased by increasing the transmit
power on a reduced set of available REs, combined with increasing
the power of common channels while keeping total radiated power
over the entire bandwidth unchanged.
[0042] In an example aspect, the carrier operating bandwidth of a
small cell may be changed. For example, a small may be operating on
a 10 MHz or a 20 MHz carrier and the bandwidth of the operating
carrier may be changed to a 5 MHz carrier. This is just an example,
not a limitation, as the small cell may be operating on a carrier
with a bandwidth of any size. In an aspect, the carrier bandwidth
of the small cell may be reduced to increase the coverage area of
the small cell by increasing the available power on the REs.
[0043] In an additional example aspect, the operating bandwidth of
the carrier of the small cell may be changed based on operational
measurements (OMs) collected at the small cell. For example, the
small cell may decrease the operating bandwidth of the carrier
based on the OMs collected by the small cell when the small cell
determines that the coverage area of the small cell may be
increased by putting more available power on the REs based on the
information derived from the collected OMs.
[0044] In an additional or optional example aspect, the bandwidth
of the operating carrier of a small cell may be configured at the
time the small cell is initially turned ON or after the initial
configuration. Additionally, the network operator may pre-configure
the various carrier bandwidths (e.g., 5 MH, 10 MHz, 20 MHz, etc.)
that may be configured at the small cell.
[0045] In an aspect, the transmit power of the common channels
and/or pilots may be increased/decreased to support an
increased/decreased coverage area of the small cell. For example,
in an aspect when the transmit power of common channels is
increased, the common channels may include, for example, common
reference signal (CRS), primary synchronization signal (PSS),
secondary synchronization signal (SSS), physical broadcast Channel
(PBCH), and physical downlink control channel (PDCCH). The transmit
powers of the common signals/pilots may be increased to support the
extended coverage area of the small cell.
[0046] In an additional aspect, traffic to pilot (T2P) values, for
example, Pa/Pb, may be increased/decreased to increase/decrease the
coverage area of the small cell. In an aspect, the target number of
hybrid automatic repeat request (HARQ) transmissions may be
increased. For example, for a given transmit power, if the target
number of HARQ transmissions is increased from 1 to 4
transmissions, a gain of 6 dB may be achieved to increase the
coverage area of the small cell. Additionally, in an aspect, block
error rate (BLER) target for HARQ processes may be increased to
increase the coverage range of the small cell.
[0047] Additionally, various parameters may be modified at the
small cell to change the coverage range of the small cell. For
example, adjusting the aggregation level for PDCCH, limiting the
number of resource blocks (RB) for PDCCH and PDSCH to keep the
total transmit power below the maximum allowed power. For example,
when pilot or control channels are boosted to improve the coverage
area of the small cell, the PDSCH transmit power may be reduced or
the number of RBs used for PDSCH may be reduced to compensate for
the increase in the pilot/overhead/control channel power. In an
aspect, when the transmit power of the common channels is
increased, the peak OTA rates at the small cell may go down as
power is being borrowed from the total power.
[0048] In an aspect, modifying parameters of the small cell may be
semi-static or dynamic. For example, the parameters may be modified
dynamically based on the estimated available backhaul capacity. In
an optional aspect, the parameters may be modified in a semi-static
manner, e.g., based on the time of day, number of users served by
the small cell, small cell deployment density, UE capability, time
of day and configuration aspects of the small cell such as MIMO
configuration. The semi-static approach may be used to avoid
frequently changing the coverage area of the small cell.
[0049] In an aspect, the parameters at the small cell may be
modified to bias configuration of the small cell towards increasing
the coverage range of the small cell or towards meeting the target
OTA rate. For example, if more UEs are outside the coverage area of
the small cell, the parameters may be modified to increase the
coverage area of the small cell. In an additional example aspect,
if more UEs are closer to the center of the small cell, the
parameters may be modified to decrease the coverage area of the
small, by reducing the transmit power of the small cell, so the
small cell may support higher OTA rates.
[0050] In an optional aspect, the transmit power of the small cell
may be reduced when it is determined that that more UEs are located
closer to the center of the small cell, rather than at the edge of
the cell or outside the coverage area of the cell. By reducing the
coverage area of the cell, the small cell may support more UEs in
that in present in the decreased coverage area and/or provide
higher peak data rates.
[0051] FIG. 3 illustrates an example methodology 300 for optimizing
coverage area of a small cell. In an aspect, at block 302,
methodology 300 may include estimating an available backhaul
capacity of a small cell. For example, in an aspect, base station
110 and/or coverage optimization manager 112 and/or backhaul
capacity estimating component 210 may be configured to estimate
available backhaul capacity of a small cell. For example, the
available backhaul capacity may be dependent on multiple factors as
described above.
[0052] Furthermore, at block 304, methodology 300 may include
determining a target OTA data rate for the small cell based at
least on the estimated available backhaul capacity. For example, in
an aspect, base station 110 and/or coverage optimization manager
112 and/or target OTA data rate identifying component 212 may be
configured to determine a target OTA data rate for the small cell
based at least on the estimated available backhaul capacity.
[0053] Additionally, at block 306, methodology 300 may include
changing a coverage area of the small cell based at least on the
determined target OTA data rate. For example, in an aspect, base
station 110 and/or coverage optimization manager 112 and/or
parameter optimizing component 114 may be configured to change the
coverage area of the small cell based at least on the determined
target OTA data rate. In an additional or optional aspect, for
example, changing the coverage area of the small cell based at
least on the determined OTA data rate may include modifying one or
more parameters of the small cell as described in reference to FIG.
2 above.
[0054] Referring to FIG. 4, an example system 400 is displayed for
optimizing coverage area of a small cell. For example, system 400
can reside at least partially within small cell 110 (FIG. 1). It is
to be appreciated that system 400 is represented as including
functional blocks, which can be functional blocks that represent
functions implemented by a processor, software, or combination
thereof (for example, firmware). System 400 includes a logical
grouping 402 of electrical components that can act in conjunction.
For instance, logical grouping 402 can include an electrical
component 404 for estimating an available backhaul capacity of a
small cell. In an aspect, electrical component 404 may comprise
backhaul capacity estimating component 210 (FIG. 2).
[0055] Additionally, logical grouping 402 can include an electrical
component 406 for determining a target OTA data rate for the small
cell based at least on the estimated available backhaul capacity.
In an aspect, electrical component 406 may comprise target OTA data
rate determining component 212 (FIG. 2). Furthermore, in an aspect,
logical grouping 402 can include an electrical component 408 for
changing a coverage area of the small cell based at least on the
determined target OTA data rate. In an aspect, electrical component
408 may comprise parameter optimization component 114 (FIGS.
1-2).
[0056] Additionally, system 400 can include a memory 410 that
retains instructions for executing functions associated with the
electrical components 404, 406, and 408, stores data used or
obtained by the electrical components 404, 406, and 408, etc. While
shown as being external to memory 410, it is to be understood that
one or more of the electrical components 404, 406, and 408 can
exist within memory 410. In one example, electrical components 404,
406, and 408 can comprise at least one processor, or each
electrical component 404, 406, and 408 can be a corresponding
module of at least one processor. Moreover, in an additional or
alternative example, electrical components 404, 406, and 408 can be
a computer program product including a computer readable medium,
where each electrical component 404, 406, and 408 can be
corresponding code.
[0057] FIG. 5 illustrates an example communication system to enable
deployment of base stations within a network environment. As shown
in FIG. 5, system 500 includes multiple base stations or Home Node
B units (HNBs) or small cells, such as, for example, HNBs 510, each
being installed in a corresponding small scale network environment,
such as, for example, in one or more user residences 530, and being
configured to serve associated, as well as alien, user equipment
(UE) 520. Each HNB 510 is further coupled to Internet 540 and a
mobile operator core network 550 via a DSL router (not shown) or,
alternatively, a cable modem (not shown).
[0058] Although aspects described herein use 3GPP terminology, it
is to be understood that the aspects may be applied to 3GPP (Rel99,
Rel5, Rel6, Rel7) technology, as well as 3GPP2 (1xRTT, 1xEV-DO
Rel0, RevA, RevB) technology and other known and related
technologies. In such aspects described herein, the owner of the
HNB 510 subscribes to mobile service, such as, for example, 3G
mobile service, offered through the mobile operator core network
550, and the UE 520 is capable to operate both in macro cellular
environment and in residential small scale network environment.
Thus, the HNB 510 is backward compatible with any existing UE
520.
[0059] Furthermore, in addition to the macro cell mobile network
550, the UE 520 can only be served by a predetermined number of
HNBs 510, namely the HNBs 510 that reside within the user's
residence 530, and cannot be in a soft handover state with the
macro network 550. The UE 520 can communicate either with the macro
network 550 or the HNBs 510, but not both simultaneously. As long
as the UE 520 is authorized to communicate with the HNB 510, within
the user's residence it is desired that the UE 520 communicate only
with the associated HNBs 510.
[0060] Referring to FIG. 6, in one aspect, one or more of small
cells 110 (FIG. 1), including coverage optimization manager 112
(FIGS. 1-2) may be represented by a specially programmed or
configured computer device 600. In one aspect of implementation,
computer device 600 may include coverage optimization manager 112
(FIGS. 1-2), such as in specially programmed computer readable
instructions or code, firmware, hardware, or some combination
thereof. Computer device 600 includes a processor 602 for carrying
out processing functions associated with one or more of components
and functions described herein. Processor 602 can include a single
or multiple set of processors or multi-core processors. Moreover,
processor 602 can be implemented as an integrated processing system
and/or a distributed processing system.
[0061] Computer device 600 further includes a memory 604, such as
for storing data used herein and/or local versions of applications
being executed by processor 602. Memory 604 can include any type of
memory usable by a computer, such as random access memory (RAM),
read only memory (ROM), tapes, magnetic discs, optical discs,
volatile memory, non-volatile memory, and any combination
thereof.
[0062] Further, computer device 600 includes a communications
component 606 that provides for establishing and maintaining
communications with one or more parties utilizing hardware,
software, and services as described herein. Communications
component 606 may carry communications between components on
computer device 600, as well as between computer device 600 and
external devices, such as devices located across a communications
network and/or devices serially or locally connected to computer
device 600. For example, communications component 606 may include
one or more buses, and may further include transmit chain
components and receive chain components associated with a
transmitter and receiver, respectively, or a transceiver, operable
for interfacing with external devices. In an additional aspect,
communications component 606 may be configured to receive one or
more pages from one or more subscriber networks. In a further
aspect, such a page may correspond to the second subscription and
may be received via the first technology type communication
services.
[0063] Additionally, computer device 600 may further include a data
store 608, which can be any suitable combination of hardware and/or
software, that provides for mass storage of information, databases,
and programs employed in connection with aspects described herein.
For example, data store 608 may be a data repository for
applications not currently being executed by processor 602 and/or
any threshold values or finger position values.
[0064] Computer device 600 may additionally include a user
interface component 610 operable to receive inputs from a user of
computer device 600 and further operable to generate outputs for
presentation to the user. User interface component 610 may include
one or more input devices, including but not limited to a keyboard,
a number pad, a mouse, a touch-sensitive display, a navigation key,
a function key, a microphone, a voice recognition component, any
other mechanism capable of receiving an input from a user, or any
combination thereof. Further, user interface component 610 may
include one or more output devices, including but not limited to a
display, a speaker, a haptic feedback mechanism, a printer, any
other mechanism capable of presenting an output to a user, or any
combination thereof.
[0065] FIG. 7 is a block diagram illustrating an example of a
hardware implementation for an apparatus 700, for example,
including coverage optimization manager 112 of FIG. 1, employing a
processing system 714 for carrying out aspects of the present
disclosure, such as method for optimizing coverage area of a small
cell. In this example, the processing system 714 may be implemented
with bus architecture, represented generally by a bus 702. The bus
702 may include any number of interconnecting buses and bridges
depending on the specific application of the processing system 714
and the overall design constraints. The bus 702 links together
various circuits including one or more processors, represented
generally by the processor 704, computer-readable media,
represented generally by the computer-readable medium 707, and one
or more components described herein, such as, but not limited to,
coverage optimization manager 112 (FIGS. 1-2). The bus 702 may also
link various other circuits such as timing sources, peripherals,
voltage regulators, and power management circuits, which are well
known in the art, and therefore, will not be described any further.
A bus interface 708 provides an interface between the bus 702 and a
transceiver 710. The transceiver 710 provides a means for
communicating with various other apparatus over a transmission
medium. Depending upon the nature of the apparatus, a user
interface 712 (e.g., keypad, display, speaker, microphone,
joystick) may also be provided.
[0066] The processor 704 is responsible for managing the bus 702
and general processing, including the execution of software stored
on the computer-readable medium 707. The software, when executed by
the processor 704, causes the processing system 714 to perform the
various functions described infra for any particular apparatus. The
computer-readable medium 707 may also be used for storing data that
is manipulated by the processor 704 when executing software.
[0067] FIG. 8 is a diagram illustrating a long term evolution (LTE)
network architecture 800 employing various apparatuses of wireless
communication system 100 (FIG. 1) and may include one or more small
cells configured to include coverage optimization manager 112
(FIGS. 1-2). The LTE network architecture 800 may be referred to as
an Evolved Packet System (EPS) 800. EPS 800 may include one or more
user equipment (UE) 802, an Evolved UMTS Terrestrial Radio Access
Network (E-UTRAN) 804, an Evolved Packet Core (EPC) 880, a Home
Subscriber Server (HSS) 820, and an Operator's IP Services 822. The
EPS can interconnect with other access networks, but for simplicity
those entities/interfaces are not shown. As shown, the EPS provides
packet-switched services, however, as those skilled in the art will
readily appreciate, the various concepts presented throughout this
disclosure may be extended to networks providing circuit-switched
services.
[0068] The E-UTRAN includes the evolved Node B (eNB) 806 and other
eNBs 808. The eNB 806 provides user and control plane protocol
terminations toward the UE 802. The eNB 808 may be connected to the
other eNBs 808 via an X2 interface (i.e., backhaul). The eNB 806
may also be referred to by those skilled in the art as a base
station, a base transceiver station, a radio base station, a radio
transceiver, a transceiver function, a basic service set (BSS), a
small cell, an extended service set (ESS), or some other suitable
terminology. The eNB 806 provides an access point to the EPC 880
for a UE 802. Examples of UEs 802 include a cellular phone, a smart
phone, a session initiation protocol (SIP) phone, a laptop, a
personal digital assistant (PDA), a satellite radio, a global
positioning system, a multimedia device, a video device, a digital
audio player (e.g., MP3 player), a camera, a game console, or any
other similar functioning device. The UE 802 may also be referred
to by those skilled in the art as a mobile station, a subscriber
station, a mobile unit, a subscriber unit, a wireless unit, a
remote unit, a mobile device, a wireless device, a wireless
communications device, a remote device, a mobile subscriber
station, an access terminal, a mobile terminal, a wireless
terminal, a remote terminal, a handset, a user agent, a mobile
client, a client, or some other suitable terminology.
[0069] The eNB 806 is connected by an S1 interface to the EPC 880.
The EPC 880 includes a Mobility Management Entity (MME) 862, other
MMEs 864, a Serving Gateway 866, and a Packet Data Network (PDN)
Gateway 868. The MME 862 is the control node that processes the
signaling between the UE 802 and the EPC 880. Generally, the MME
862 provides bearer and connection management. All user IP packets
are transferred through the Serving Gateway 866, which itself is
connected to the PDN Gateway 868. The PDN Gateway 868 provides UE
IP address allocation as well as other functions. The PDN Gateway
868 is connected to the Operator's IP Services 822. The Operator's
IP Services 822 include the Internet, the Intranet, an IP
Multimedia Subsystem (IMS), and a PS Streaming Service (PSS).
[0070] Referring to FIG. 9, an access network 900 in a UTRAN
architecture is illustrated, and may include one or more base
stations or small cells configured to include coverage optimization
manager 112 (FIGS. 1-2). The multiple access wireless communication
system includes multiple cellular regions (cells), including cells
902, 904, and 906, each of which may include one or more sectors
and which may be one or more small cells 110 of FIG. 1. The
multiple sectors can be formed by groups of antennas with each
antenna responsible for communication with UEs in a portion of the
cell. For example, in cell 902, antenna groups 912, 914, and 916
may each correspond to a different sector. In cell 904, antenna
groups 919, 920, and 922 each correspond to a different sector. In
cell 906, antenna groups 924, 926, and 928 each correspond to a
different sector. The cells 902, 904 and 906 may include several
wireless communication devices, e.g., User Equipment or UEs, for
example, including UEs 122, 132, and 142 of FIG. 1, which may be in
communication with one or more sectors of each cell 902, 904 or
906. For example, UEs 930 and 932 may be in communication with
NodeB 942, UEs 934 and 936 may be in communication with NodeB 944,
and UEs 939 and 940 can be in communication with NodeB 946. Here,
each NodeB 942, 944, 946 is configured to provide an access point
for all the UEs 930, 932, 934, 936, 938, 940 in the respective
cells 902, 904, and 906. Additionally, each NodeB 942, 944, 946 and
UEs 930, 932, 934, 936, 938, 940 may be UEs 122, 132 of FIG. 1 and
may perform the methods outlined herein.
[0071] As the UE 934 moves from the illustrated location in cell
904 into cell 906, a serving cell change (SCC) or handover may
occur in which communication with the UE 934 transitions from the
cell 904, which may be referred to as the source cell, to cell 906,
which may be referred to as the target cell. Management of the
handover procedure may take place at the UE 934, at the Node Bs
corresponding to the respective cells, at a EPC 880 (FIG. 8), or at
another suitable node in the wireless network. For example, during
a call with the source cell 904, or at any other time, the UE 934
may monitor various parameters of the source cell 904 as well as
various parameters of neighboring cells such as cells 906 and 902.
Further, depending on the quality of these parameters, the UE 934
may maintain communication with one or more of the neighboring
cells. During this time, the UE 934 may maintain an Active Set,
that is, a list of cells that the UE 934 is simultaneously
connected to (i.e., the UTRA cells that are currently assigning a
downlink dedicated physical channel DPCH or fractional downlink
dedicated physical channel F-DPCH to the UE 934 may constitute the
Active Set). In any case, UE 934 may execute reselection manager
104 to perform the reselection operations described herein.
[0072] Further, the modulation and multiple access scheme employed
by the access network 900 may vary depending on the particular
telecommunications standard being deployed. By way of example, the
standard may include Evolution-Data Optimized (EV-DO) or Ultra
Mobile Broadband (UMB). EV-DO and UMB are air interface standards
promulgated by the 3rd Generation Partnership Project 2 (3GPP2) as
part of the CDMA2000 family of standards and employs CDMA to
provide broadband Internet access to mobile stations. The standard
may alternately be Universal Terrestrial Radio Access (UTRA)
employing Wideband-CDMA (W-CDMA) and other variants of CDMA, such
as TD-SCDMA; Global System for Mobile Communications (GSM)
employing TDMA; and Evolved UTRA (E-UTRA), Ultra Mobile Broadband
(UMB), IEEE 902.11 (Wi-Fi), IEEE 902.16 (WiMAX), IEEE 902.20, and
Flash-OFDM employing OFDMA. UTRA, E-UTRA, UMTS, LTE, LTE Advanced,
and GSM are described in documents from the 3GPP organization.
CDMA2000 and UMB are described in documents from the 3GPP2
organization. The actual wireless communication standard and the
multiple access technology employed will depend on the specific
application and the overall design constraints imposed on the
system.
[0073] FIG. 10 is a block diagram of a NodeB 1010 in communication
with a UE 1050, where the NodeB 1010 may one or more of small cells
110 and/or may include coverage optimization manager 112 (FIGS.
1-2). In the downlink communication, a transmit processor 1020 may
receive data from a data source 1012 and control signals from a
controller/processor 1040. The transmit processor 1020 provides
various signal processing functions for the data and control
signals, as well as reference signals (e.g., pilot signals). For
example, the transmit processor 1020 may provide cyclic redundancy
check (CRC) codes for error detection, coding and interleaving to
facilitate forward error correction (FEC), mapping to signal
constellations based on various modulation schemes (e.g., binary
phase-shift keying (BPSK), quadrature phase-shift keying (QPSK),
M-phase-shift keying (M-PSK), M-quadrature amplitude modulation
(M-QAM), and the like), spreading with orthogonal variable
spreading factors (OVSF), and multiplying with scrambling codes to
produce a series of symbols. Channel estimates from a channel
processor 1044 may be used by a controller/processor 1040 to
determine the coding, modulation, spreading, and/or scrambling
schemes for the transmit processor 1020. These channel estimates
may be derived from a reference signal transmitted by the UE 1050
or from feedback from the UE 1050. The symbols generated by the
transmit processor 1020 are provided to a transmit frame processor
1030 to create a frame structure. The transmit frame processor 1030
creates this frame structure by multiplexing the symbols with
information from the controller/processor 1040, resulting in a
series of frames. The frames are then provided to a transmitter
1032, which provides various signal conditioning functions
including amplifying, filtering, and modulating the frames onto a
carrier for downlink transmission over the wireless medium through
antenna 1034. The antenna 1034 may include one or more antennas,
for example, including beam steering bidirectional adaptive antenna
arrays or other similar beam technologies.
[0074] At the UE 1050, a receiver 1054 receives the downlink
transmission through an antenna 1052 and processes the transmission
to recover the information modulated onto the carrier. The
information recovered by the receiver 1054 is provided to a receive
frame processor 1060, which parses each frame, and provides
information from the frames to a channel processor 1094 and the
data, control, and reference signals to a receive processor 1070.
The receive processor 1070 then performs the inverse of the
processing performed by the transmit processor 1020 in the NodeB
1010. More specifically, the receive processor 1070 descrambles and
de-spreads the symbols, and then determines the most likely signal
constellation points transmitted by the NodeB 1010 based on the
modulation scheme. These soft decisions may be based on channel
estimates computed by the channel processor 1094. The soft
decisions are then decoded and de-interleaved to recover the data,
control, and reference signals. The CRC codes are then checked to
determine whether the frames were successfully decoded. The data
carried by the successfully decoded frames will then be provided to
a data sink 1072, which represents applications running in the UE
1050 and/or various user interfaces (e.g., display). Control
signals carried by successfully decoded frames will be provided to
a controller/processor 1090. When frames are unsuccessfully decoded
by the receiver processor 1070, the controller/processor 1090 may
also use an acknowledgement (ACK) and/or negative acknowledgement
(NACK) protocol to support retransmission requests for those
frames.
[0075] In the uplink, data from a data source 1078 and control
signals from the controller/processor 1090 are provided to a
transmit processor 1080. The data source 1078 may represent
applications running in the UE 1050 and various user interfaces
(e.g., keyboard). Similar to the functionality described in
connection with the downlink transmission by the NodeB 1010, the
transmit processor 1080 provides various signal processing
functions including CRC codes, coding and interleaving to
facilitate FEC, mapping to signal constellations, spreading with
OVSFs, and scrambling to produce a series of symbols. Channel
estimates, derived by the channel processor 1094 from a reference
signal transmitted by the NodeB 1010 or from feedback contained in
the midamble transmitted by the NodeB 1010, may be used to select
the appropriate coding, modulation, spreading, and/or scrambling
schemes. The symbols produced by the transmit processor 10100 will
be provided to a transmit frame processor 1082 to create a frame
structure. The transmit frame processor 1082 creates this frame
structure by multiplexing the symbols with information from the
controller/processor 1090, resulting in a series of frames. The
frames are then provided to a transmitter 1056, which provides
various signal conditioning functions including amplification,
filtering, and modulating the frames onto a carrier for uplink
transmission over the wireless medium through the antenna 1052.
[0076] The uplink transmission is processed at the NodeB 1010 in a
manner similar to that described in connection with the receiver
function at the UE 1050. A receiver 1035 receives the uplink
transmission through the antenna 1034 and processes the
transmission to recover the information modulated onto the carrier.
The information recovered by the receiver 1035 is provided to a
receive frame processor 1036, which parses each frame, and provides
information from the frames to the channel processor 1044 and the
data, control, and reference signals to a receive processor 1038.
The receive processor 1038 performs the inverse of the processing
performed by the transmit processor 1080 in the UE 1050. The data
and control signals carried by the successfully decoded frames may
then be provided to a data sink 1039 and the controller/processor,
respectively. If some of the frames were unsuccessfully decoded by
the receive processor, the controller/processor 1040 may also use
an acknowledgement (ACK) and/or negative acknowledgement (NACK)
protocol to support retransmission requests for those frames.
[0077] The controller/processors 1040 and 1090 may be used to
direct the operation at the NodeB 1010 and the UE 1050,
respectively. For example, the controller/processors 1040 and 1090
may provide various functions including timing, peripheral
interfaces, voltage regulation, power management, and other control
functions. The computer readable media of memories 1042 and 1092
may store data and software for the NodeB 1010 and the UE 1050,
respectively. A scheduler/processor 1046 at the NodeB 1010 may be
used to allocate resources to the UEs and schedule downlink and/or
uplink transmissions for the UEs.
[0078] Several aspects of a telecommunications system have been
presented with reference to a W-CDMA system. As those skilled in
the art will readily appreciate, various aspects described
throughout this disclosure may be extended to other
telecommunication systems, network architectures and communication
standards.
[0079] By way of example, various aspects may be extended to other
UMTS systems such as TD-SCDMA, High Speed Downlink Packet Access
(HSDPA), High Speed Uplink Packet Access (HSUPA), High Speed Packet
Access Plus (HSPA+) and TD-CDMA. Various aspects may also be
extended to systems employing Long Term Evolution (LTE) (in FDD,
TDD, or both modes), LTE-Advanced (LTE-A) (in FDD, TDD, or both
modes), CDMA2000, Evolution-Data Optimized (EV-DO), Ultra Mobile
Broadband (UMB), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE
802.20, Ultra-Wideband (UWB), Bluetooth, and/or other suitable
systems. The actual telecommunication standard, network
architecture, and/or communication standard employed will depend on
the specific application and the overall design constraints imposed
on the system.
[0080] In accordance with various aspects of the disclosure, an
element, or any portion of an element, or any combination of
elements may be implemented with a "processing system" that
includes one or more processors. Examples of processors include
microprocessors, microcontrollers, digital signal processors
(DSPs), field programmable gate arrays (FPGAs), programmable logic
devices (PLDs), state machines, gated logic, discrete hardware
circuits, and other suitable hardware configured to perform the
various functionality described throughout this disclosure. One or
more processors in the processing system may execute software.
Software shall be construed broadly to mean instructions,
instruction sets, code, code segments, program code, programs,
subprograms, software modules, applications, software applications,
software packages, routines, subroutines, objects, executables,
threads of execution, procedures, functions, etc., whether referred
to as software, firmware, middleware, microcode, hardware
description language, or otherwise. The software may reside on a
computer-readable medium. The computer-readable medium may be a
non-transitory computer-readable medium. A non-transitory
computer-readable medium includes, by way of example, a magnetic
storage device (e.g., hard disk, floppy disk, magnetic strip), an
optical disk (e.g., compact disk (CD), digital versatile disk
(DVD)), a smart card, a flash memory device (e.g., card, stick, key
drive), random access memory (RAM), read only memory (ROM),
programmable ROM (PROM), erasable PROM (EPROM), electrically
erasable PROM (EEPROM), a register, a removable disk, and any other
suitable medium for storing software and/or instructions that may
be accessed and read by a computer.
[0081] The computer-readable medium may also include, by way of
example, a carrier wave, a transmission line, and any other
suitable medium for transmitting software and/or instructions that
may be accessed and read by a computer. The computer-readable
medium may be resident in the processing system, external to the
processing system, or distributed across multiple entities
including the processing system. The computer-readable medium may
be embodied in a computer-program product. By way of example, a
computer-program product may include a computer-readable medium in
packaging materials. Those skilled in the art will recognize how
best to implement the described functionality presented throughout
this disclosure depending on the particular application and the
overall design constraints imposed on the overall system.
[0082] It is to be understood that the specific order or hierarchy
of steps in the methods disclosed is an illustration of exemplary
processes. Based upon design preferences, it is understood that the
specific order or hierarchy of steps in the methods may be
rearranged. The accompanying method claims present elements of the
various steps in a sample order, and are not meant to be limited to
the specific order or hierarchy presented unless specifically
recited therein.
[0083] The previous description is provided to enable any person
skilled in the art to practice the various aspects described
herein. Various modifications to these aspects will be readily
apparent to those skilled in the art, and the generic principles
defined herein may be applied to other aspects. Thus, the claims
are not intended to be limited to the aspects shown herein, but is
to be accorded the full scope consistent with the language of the
claims, wherein reference to an element in the singular is not
intended to mean "one and only one" unless specifically so stated,
but rather "one or more." Unless specifically stated otherwise, the
term "some" refers to one or more. A phrase referring to "at least
one of" a list of items refers to any combination of those items,
including single members. As an example, "at least one of: a, b, or
c" is intended to cover: a; b; c; a and b; a and c; b and c; and a,
b and c. All structural and functional equivalents to the elements
of the various aspects described throughout this disclosure that
are known or later come to be known to those of ordinary skill in
the art are expressly incorporated herein by reference and are
intended to be encompassed by the claims. Moreover, nothing
disclosed herein is intended to be dedicated to the public
regardless of whether such disclosure is explicitly recited in the
claims. No claim element is to be construed under the provisions of
35 U.S.C. .sctn.112, sixth paragraph, unless the element is
expressly recited using the phrase "means for" or, in the case of a
method claim, the element is recited using the phrase "step
for."
* * * * *